Foraminiferida are an order of rhizopod protozoans characterized by the presence of granuloreticulopods and a test. Together with the Order Athalamida, they are the only Rhizopoda with anastomozing pseudopodia that contain granules (Fig. 1). The difference between the Athalamida and Foraminiferida is arbitrary because some foraminifera are known to leave their tests and move about, later returning to them (Marszalek, 1969), and some Athalamida attach foreign particles to the cell surface.

A systematic classification generally reflects accurately the state of knowledge of a group. As information concerning the group increases, both similarities and differences become more apparent. New characters then may be utilized to develop a more complex classification, that better serves to indicate presumed relationships. Assuming that organisms have evolved through time, the more detailed classification may also prove more valuable to the biostratigrapher.

Benthic foraminifera live in a wide variety of marine habitats, from marshes to abyssal plains. Both epifaunal and infaunal adaptations are present. The distribution of species is controlled by a complex of abiotic and biotic variables of the environment, usually resulting in a depth-zonation of assemblages on continental margins.

The composition of the substrate may have a direct or indirect influence on the constitution of the assemblage. Laboratory studies and field observations demonstrate the effects of temperature and salinity variations, particularly on nearshore species. Many calcareous species have algal or chloroplast symbionts; their distribution is partly controlled by light tolerance.

Benthic foraminifera are omnivorous and feed mainly by the pseudopodia. Large supply of nutrients, as in areas of upwelling or water mixing, may give rise to large blooms of opportunistic species.

Marine marshes of diverse geographic locations support some common species. Deep bathyal or abyssal species are widespread, but dominance patterns are apparently associated with identifiable water masses, although causal relations are unclear.

The history of investigations of planktonic foraminifera leading to their current, wide applications in biostratigraphic correlation of Mesozoic and Cenozoic marine sediments can be traced to the discovery by Owen (1867) of the floating habit of certain foraminifera, later confirmed by Brady (1884), and the recognition by Murray and Renard (1891) that their shells constitute a major portion of deep-sea sediments over large regions of the seafloor. The utilitarian value of planktonic foraminifera in paleoecological analysis is also widely accepted today. Fortunately for students of paleoecology, many species of planktonic foraminifera are still extant and live in large numbers in all oceanic regions. Their areal, vertical and seasonal occurrences have been resolved to such a degree that a global synthesis of their distribution patterns is now available (e.g. Bradshaw, 1959; Belyaeva, 1964; Be and Tolderlund, 1971).

Biogeography is concerned with recording and explaining the distribution of organisms in space and time. In their search for patterns of distribution, biogeographers have classified the surface of the earth into a hierarchical scheme of ecological units (e.g. Kauffman and Scott, 1976). The basic biogeographic units are realms and provinces. A faunal realm is a large area about the size of a continent while provinces are subdivisions within a realm. An appreciation of the scale involved is gained by considering a current classification of the terrestial world (Udvardy, 1975) which contains 8 realms and 172 provinces.

Since the inception of their use in commercial micropaleontology, benthic foraminifera have proven to be eminently useful in the solution of geological problems. The utilitarian credentials of benthic foraminifera in estimating paleodepths from marsh through neritic environments with a reasonable degree of accuracy and to indicate approximate ages (viz. subdivision of series/epochs) have been established in both commercial and academic applications. Benthic foraminifera are generally more resistant to dissolution than planktonic foraminifera, and have wide distributions; many taxa have restricted stratlgraphic ranges, making them suitable for correlation and paleo-environmental studies. Yet, three problems have tended to limit the utility of benthic foraminifera: 1) there is a lack of uniformity in taxonomy (Boltovskoy, 1980; Douglas & Woodruff, 1982); 2) attempts to erect zonal schemes using benthic foraminifera have resulted in boundaries which are later proven to be diachronous relative to planktonic zonatlons (e.g. the California provincial stages, Poore, 1976); and 3) attempts to interpret paleodepths from deep-sea benthic foraminifera have produced widely-varying results. One could perhaps conclude, as Boltovskoy (1965a) did over a decade ago, that these problems indicate “…the near future of this science is rather bleak.”

The Study of Cenozoic planktonic foraminifera has benefited in the last 1–1/2 decades by Deep Sea Drilling retrieval of many cored sections from the major ocean basins of the world. The stratigraphy of planktonic foraminiferal species in these ocean basins has provided important data on evolutionary lineages of species and biostratigraphic utility of species. The geographic coverage of the oceans has given a clearer picture of the biogeography of species and of past oceanographic conditions. It has become clear that the evolution of planktonic foraminifera was controlled by oceanographic and climatic events related to the redistribution of land and sea. The purpose of this presentation is to summarize the major patterns of the paleobiogeography of planktonic foraminifera during the Cenozoic.

The evolutionary development of Mesozoic planktic foraminifera is almost exclusively restricted to the Cretaceous Period. Diversity is relatively low until the Late Cretaceous (Turonian to Maastrichtian) when numerous architectural forms are found in the record. Just as remarkable, and more so to this author, is the nearly complete extinction of the group at the end of the Maastrichtian. My purpose will be to attempt to briefly categorize the major areas of study and to describe the numerous problems yet to be solved by workers in the field.

Fusulinacea are an extinct superfamily of small to large, to very laurge, calcareous Foraminiferida. They were entirely marine sind made their first appearance near the end of Early Carboniferous time (Text-fig. 1). They thrived during Middle and Late Carboniferous and Permian time. During that 100 million year existence, they evolved more than 150 genera and more than 6000 species before starting a decline in the later part of the Permicm and finally becoming extinct near the end of that period. Members of the Fusulinacea became giants, typically reaching 1 cm or more in length, and some became enormous giants, reaching 4 and 5 cm in length in the mid-Permian, and a few as much as 10 cm! Not bad for a single celled organism. Fusulinaceans are usually large enough that field geologists can spot them quickly in their stratigraphic units.

Literature on foraminifera in general is quite accessible and useable. Cushman's (1948) textbook, combined with the treatise of Loeblich and Tappan (1964), suffices for most generic definitions. Loeblich and Tappan's (1964) work is, in addition, the most comprehensive treatment of the general biology, ecology, classification, and stratigraphic distribution of the foraminifera. On a specific level, the preeminent reference works on the foraminifera are Ellis and Messina's (1940–1982) Catalogue of the Foraminifera, Sherborn's (1888) Bibliography of the Foraminifera from 1765–1888 and his (1893–1896) Index to Genera and Species of the Foraminifera, and Cushman's (1950) Card Catalogue on microfilm. Important as well are Brady's Challenger report (1884), Cushman's (1910–1916) monograph on the North Pacific Ocean foraminifera and his (1918–1931) Foraminifera of the Atlantic Ocean, to mention a few of the works on the Recent foraminifera; a knowledge of Recent foraminifera is important, for a large number of agglutinate foraminiferal genera have stratigraphic ranges from Paleozoic to Recent. Brady's (1876) monograph of Carboniferous and Permian foraminifera is also important.